1. Progress towards nanometre level beam stabilisation
Neven Blaskovic, Talitha Bromwich, Philip Burrows, Glenn Christian, Colin Perry, Rebecca Ramjiawan
John Adams Institute, Oxford University

2. Outline Introduction to our work at ATF Set-up and components
Stripline and cavity BPM performance
Intra-train feedback results
Neven Blaskovic 2

3. International Linear Collider (ILC)
Introduction
International Linear Collider (ILC)
The next large particle accelerator will most likely be a linear electron-positron collider
A proposed design is the International Linear Collider (ILC):
Neven Blaskovic 3

4. Feedback on Nanosecond Timescales (FONT)
Introduction
Feedback on Nanosecond Timescales (FONT)
Linear colliders are single-pass machines
Successful collision of bunches is critical
A fast feedback system is required, e.g. FONT:
Neven Blaskovic 4

5. Accelerator Test Facility (ATF), Japan
Introduction
Accelerator Test Facility (ATF), Japan
We test the FONT feedback system at ATF, the Accelerator Test Facility for the future ILC:
Linear accelerator
Damping ring
Extraction line
90 m
Neven Blaskovic 5

6. Feedback at the Accelerator Test Facility
Introduction
Feedback at the Accelerator Test Facility
ATF provides pairs of bunches travelling in the extraction line with ~200 ns bunch separation
We measure the position of the first bunch in order to correct the path of the second bunch
Extraction line
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7. Feedback at the Accelerator Test Facility
Introduction
Feedback at the Accelerator Test Facility
IPC
IPB
IPA
IPK M P3 P2 K2 K1
Key P2 P3 M
Stripline BPMs
IPA
IPB
IPC
Cavity BPMs
Processor
Processor
Processor
Amplifier
Processor
Processor
Processor
Amplifier
Amplifier
Processor
Down mixer
Board
Digital board
Amplifier
Kicker amplifier
Board
Board K1 K2
IPK
Stripline kickers
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8. Upstream Feedback Results IPC IPB IPA IPK M P3 P2 K2 K1 Processor
Amplifier
Processor
Processor
Processor
Amplifier
Amplifier
Board
Board
Neven Blaskovic 8

9. Stripline BPM resolution: 291 ± 10 nm
Results – Upstream Feedback
Stripline BPM resolution
Stripline BPM resolution: 291 ± 10 nm
Published in PRSTAB 18, (2015)
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10. Position stabilisation upstream
Results – Upstream Feedback
Position stabilisation upstream
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11. Position stabilisation upstream
Results – Upstream Feedback
Position stabilisation upstream
Factor ~3 improvement
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12. Position stabilisation propagated to the IP
Results – Upstream Feedback
Position stabilisation propagated to the IP
y position
y’ angle
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13. Position stabilisation propagated to the IP
Results – Upstream Feedback
Position stabilisation propagated to the IP
Propagating results to IP suggests beam stabilisation to a few nm – challenge is to measure this!
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14. Results IP Feedback IPC IPB IPA IPK M P3 P2 K2 K1 Processor Processor
Amplifier
Processor
Processor
Processor
Amplifier
Amplifier
Board
Board
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15. IP BPM resolution IP BPM resolution: ~50 nm Results – IP Feedback
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16. Position stabilisation in the IP region
Results – IP Feedback
Position stabilisation in the IP region
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17. Position stabilisation in the IP region
Results – IP Feedback
Position stabilisation in the IP region
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18. Position stabilisation in the IP region
Results – IP Feedback
Position stabilisation in the IP region
stabilised to ~75 nm
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19. Position stabilisation in the IP region
Results – IP Feedback
Position stabilisation in the IP region
Feedback off
Feedback on
Prediction
Performance with feedback on matches prediction (assuming a perfect feedback system) for a range of incoming beam conditions
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20. Conclusions Upstream feedback: 2 BPMs to drive 2 kickers
Stripline BPM resolution: ~300 nm
Local beam stabilisation: ~500 nm
Potential for nm-level beam stabilisation at the IP
IP feedback: 1 BPM to drive 1 kicker
IP BPM resolution: ~50 nm
Local beam stabilisation: ~75 nm
Work ongoing to improve IP BPM resolution
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21. Thank you for your interest and support!
Neven Blaskovic 21